1. Technical Field
The present invention relates to a line thermal printer including a line thermal head that performs printing by the selective generation of heat of a plurality of heating elements. The heating elements are disposed so as to fate the entire area of a recording sheet in a width direction of the recording sheet, and selectively generate heat. Particularly, the present invention relates to a line thermal printer that prevents foreign materials from being bitten by a line thermal head.
2. Related Art
Conventional line thermal printers are known (for example, see Japanese Unexamined Patent Application Publication No. 2006-7541).
The line thermal printer will be described with reference to FIG. 2.
A platen roller 32, and a line thermal head 33 disposed above the platen roller 32 are provided in a frame 31a. A recording sheet 34 is fed between the line thermal head 33 and the platen roller 32.
Further, the line thermal head 33 is mounted on a long head mounting part 35, and ends of a pair of head levers 36 are fixed to both ends of the head mounting part 35 in a longitudinal direction of the head mounting part.
In addition, right ends of the head levers 36 in FIG. 2 are supported by a pivot 37 that is supported by side plates of the frame 31a, and the ends of the head levers to which the line thermal head 33 is fixed can be rotated about the pivot 37.
Since the line thermal printer is a thermal transfer printer, an ink ribbon 39 received in a ribbon cassette 38 is led between the platen roller 32 and the line thermal head 33. Meanwhile, when the line thermal printer performs printing while a thermal recording sheet is used as the recording sheet, the ink ribbon 39 does not need to be used.
Further, a paper feed roller 40 and a pressing roller 41 are provided on the left side of the platen roller 32 in FIG. 2. The recording sheet 34, which is pressed and interposed between the paper feed roller 40 and the pressing roller 41, can be fed in a feed direction, which is indicated by arrow A, or a direction opposite to the feed direction that is a right direction.
A ribbon peeling member 43 is provided downstream of the head mounting part 35 in the feed direction of the recording sheet 34 so that a heat insulating material 42 is provided between the ribbon peeling member and the head mounting part.
The printing operation of the thermal printer 31 in the related art will be described. When the head levers 36 are rotated clockwise and the line thermal head 33 is in a heat-up state, the ribbon cassette 38 is mounted in the frame 31a. Accordingly, the ink ribbon 39 is led between the platen roller 32 and the line thermal head 33.
After that, the recording sheet 34, which is pressed and interposed between the paper feed roller 40 and the pressing roller 41, is fed in a direction opposite to the feed direction that is indicated by arrow A, and is fed between the platen roller 32 and the line thermal head 33 that is in a heat-up state.
When an end 34a of the recording sheet 34 is fed to the vicinity of the paper feed roller 40, the heading of the recording sheet 34 is performed and the head-down of the line thermal head 33 is performed.
If the plurality of the heating elements of the line thermal head 33, which is in a head-down state, selectively generates heat on the basis of print information, and the recording sheet 34 is fed in the direction indicated by arrow A, the ink of the ink ribbon 39 is thermally transferred onto the recording sheet. As a result, a desired image may be printed on the recording sheet 34.
However, there are foreign materials, such as dust, grains of sand, or coatings of the thermal recording sheet, on the recording sheet 34 and the foreign materials are hard. Accordingly, if the foreign materials are bitten by the line thermal head 33, the line thermal head is damaged. For this reason, there is a concern that print quality on the recording sheet 34 deteriorates.
These and other drawbacks exist.